1. Technical Field
The present invention relates to a liquid column member of a liquid tank, the liquid column member of a liquid tank being attached to a tank body and faced by a photosensor for sensing the liquid level of the tank body, to a liquid tank, and to a droplet discharge device.
2. Related Art
A conventional droplet discharge device that is provided with a sub tank (liquid tank) for storing a functional liquid that is fed to a functional droplet discharge head, and a liquid column pipe (liquid column member) provided with a liquid level detecting means for detecting the liquid level of the functional liquid stored in the sub tank is known as a droplet discharge device that is provided with the type of liquid column member and liquid tank described above (see Japanese Laid-Open Patent Publication No. 2008-238125). The functional liquid is force-fed from a main tank to the sub tank, and a valve provided in front of the sub tank is opened, whereby the functional liquid is supplied to the sub tank. The liquid level detecting means has an upper-limit sensor and a lower-limit sensor, and by maintaining the level of the functional liquid in the sub tank between these two sensors, the hydraulic head pressure value is maintained with respect to the droplet discharge head, and the discharged quantity is stabilized.